tools/perf/util/probe-finder.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * probe-finder.c : C expression to kprobe event converter
   4  *
   5  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   6  */
   7
   8 #include <inttypes.h>
   9 #include <sys/utsname.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include <fcntl.h>
  13 #include <errno.h>
  14 #include <stdio.h>
  15 #include <unistd.h>
  16 #include <stdlib.h>
  17 #include <string.h>
  18 #include <stdarg.h>
  19 #include <dwarf-regs.h>
  20
  21 #include <linux/bitops.h>
  22 #include <linux/zalloc.h>
  23 #include "event.h"
  24 #include "dso.h"
  25 #include "debug.h"
  26 #include "intlist.h"
  27 #include "strbuf.h"
  28 #include "strlist.h"
  29 #include "symbol.h"
  30 #include "probe-finder.h"
  31 #include "probe-file.h"
  32 #include "string2.h"
  33
  34 #ifdef HAVE_DEBUGINFOD_SUPPORT
  35 #include <elfutils/debuginfod.h>
  36 #endif
  37
  38 /* Kprobe tracer basic type is up to u64 */
  39 #define MAX_BASIC_TYPE_BITS     64
  40
  41 /* Dwarf FL wrappers */
  42 static char *debuginfo_path;    /* Currently dummy */
  43
  44 static const Dwfl_Callbacks offline_callbacks = {
  45         .find_debuginfo = dwfl_standard_find_debuginfo,
  46         .debuginfo_path = &debuginfo_path,
  47
  48         .section_address = dwfl_offline_section_address,
  49
  50         /* We use this table for core files too.  */
  51         .find_elf = dwfl_build_id_find_elf,
  52 };
  53
  54 /* Get a Dwarf from offline image */
  55 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  56                                          const char *path)
  57 {
  58         GElf_Addr dummy;
  59         int fd;
  60
  61         fd = open(path, O_RDONLY);
  62         if (fd < 0)
  63                 return fd;
  64
  65         dbg->dwfl = dwfl_begin(&offline_callbacks);
  66         if (!dbg->dwfl)
  67                 goto error;
  68
  69         dwfl_report_begin(dbg->dwfl);
  70         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  71         if (!dbg->mod)
  72                 goto error;
  73
  74         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  75         if (!dbg->dbg)
  76                 goto error;
  77
  78         dwfl_module_build_id(dbg->mod, &dbg->build_id, &dummy);
  79
  80         dwfl_report_end(dbg->dwfl, NULL, NULL);
  81
  82         return 0;
  83 error:
  84         if (dbg->dwfl)
  85                 dwfl_end(dbg->dwfl);
  86         else
  87                 close(fd);
  88         memset(dbg, 0, sizeof(*dbg));
  89
  90         return -ENOENT;
  91 }
  92
  93 static struct debuginfo *__debuginfo__new(const char *path)
  94 {
  95         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  96         if (!dbg)
  97                 return NULL;
  98
  99         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 100                 zfree(&dbg);
 101         if (dbg)
 102                 pr_debug("Open Debuginfo file: %s\n", path);
 103         return dbg;
 104 }
 105
 106 enum dso_binary_type distro_dwarf_types[] = {
 107         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 108         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 109         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 110         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 111         DSO_BINARY_TYPE__MIXEDUP_UBUNTU_DEBUGINFO,
 112         DSO_BINARY_TYPE__NOT_FOUND,
 113 };
 114
 115 struct debuginfo *debuginfo__new(const char *path)
 116 {
 117         enum dso_binary_type *type;
 118         char buf[PATH_MAX], nil = '\0';
 119         struct dso *dso;
 120         struct debuginfo *dinfo = NULL;
 121
 122         /* Try to open distro debuginfo files */
 123         dso = dso__new(path);
 124         if (!dso)
 125                 goto out;
 126
 127         for (type = distro_dwarf_types;
 128              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 129              type++) {
 130                 if (dso__read_binary_type_filename(dso, *type, &nil,
 131                                                    buf, PATH_MAX) < 0)
 132                         continue;
 133                 dinfo = __debuginfo__new(buf);
 134         }
 135         dso__put(dso);
 136
 137 out:
 138         /* if failed to open all distro debuginfo, open given binary */
 139         return dinfo ? : __debuginfo__new(path);
 140 }
 141
 142 void debuginfo__delete(struct debuginfo *dbg)
 143 {
 144         if (dbg) {
 145                 if (dbg->dwfl)
 146                         dwfl_end(dbg->dwfl);
 147                 free(dbg);
 148         }
 149 }
 150
 151 /*
 152  * Probe finder related functions
 153  */
 154
 155 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 156 {
 157         struct probe_trace_arg_ref *ref;
 158         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 159         if (ref != NULL)
 160                 ref->offset = offs;
 161         return ref;
 162 }
 163
 164 /*
 165  * Convert a location into trace_arg.
 166  * If tvar == NULL, this just checks variable can be converted.
 167  * If fentry == true and vr_die is a parameter, do heuristic search
 168  * for the location fuzzed by function entry mcount.
 169  */
 170 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 171                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 172                                      unsigned int machine,
 173                                      struct probe_trace_arg *tvar)
 174 {
 175         Dwarf_Attribute attr;
 176         Dwarf_Addr tmp = 0;
 177         Dwarf_Op *op;
 178         size_t nops;
 179         unsigned int regn;
 180         Dwarf_Word offs = 0;
 181         bool ref = false;
 182         const char *regs;
 183         int ret, ret2 = 0;
 184
 185         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 186                 goto static_var;
 187
 188         /* Constant value */
 189         if (dwarf_attr(vr_die, DW_AT_const_value, &attr) &&
 190             immediate_value_is_supported()) {
 191                 Dwarf_Sword snum;
 192
 193                 if (!tvar)
 194                         return 0;
 195
 196                 dwarf_formsdata(&attr, &snum);
 197                 ret = asprintf(&tvar->value, "\\%ld", (long)snum);
 198
 199                 return ret < 0 ? -ENOMEM : 0;
 200         }
 201
 202         /* TODO: handle more than 1 exprs */
 203         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 204                 return -EINVAL; /* Broken DIE ? */
 205         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 206                 ret = dwarf_entrypc(sp_die, &tmp);
 207                 if (ret)
 208                         return -ENOENT;
 209
 210                 if (probe_conf.show_location_range &&
 211                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 212                         ret2 = -ERANGE;
 213                 } else if (addr != tmp ||
 214                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 215                         return -ENOENT;
 216                 }
 217
 218                 ret = dwarf_highpc(sp_die, &tmp);
 219                 if (ret)
 220                         return -ENOENT;
 221                 /*
 222                  * This is fuzzed by fentry mcount. We try to find the
 223                  * parameter location at the earliest address.
 224                  */
 225                 for (addr += 1; addr <= tmp; addr++) {
 226                         if (dwarf_getlocation_addr(&attr, addr, &op,
 227                                                    &nops, 1) > 0)
 228                                 goto found;
 229                 }
 230                 return -ENOENT;
 231         }
 232 found:
 233         if (nops == 0)
 234                 /* TODO: Support const_value */
 235                 return -ENOENT;
 236
 237         if (op->atom == DW_OP_addr) {
 238 static_var:
 239                 if (!tvar)
 240                         return ret2;
 241                 /* Static variables on memory (not stack), make @varname */
 242                 ret = strlen(dwarf_diename(vr_die));
 243                 tvar->value = zalloc(ret + 2);
 244                 if (tvar->value == NULL)
 245                         return -ENOMEM;
 246                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 247                 tvar->ref = alloc_trace_arg_ref((long)offs);
 248                 if (tvar->ref == NULL)
 249                         return -ENOMEM;
 250                 return ret2;
 251         }
 252
 253         /* If this is based on frame buffer, set the offset */
 254         if (op->atom == DW_OP_fbreg) {
 255                 if (fb_ops == NULL)
 256                         return -ENOTSUP;
 257                 ref = true;
 258                 offs = op->number;
 259                 op = &fb_ops[0];
 260         }
 261
 262         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 263                 regn = op->atom - DW_OP_breg0;
 264                 offs += op->number;
 265                 ref = true;
 266         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 267                 regn = op->atom - DW_OP_reg0;
 268         } else if (op->atom == DW_OP_bregx) {
 269                 regn = op->number;
 270                 offs += op->number2;
 271                 ref = true;
 272         } else if (op->atom == DW_OP_regx) {
 273                 regn = op->number;
 274         } else {
 275                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 276                 return -ENOTSUP;
 277         }
 278
 279         if (!tvar)
 280                 return ret2;
 281
 282         regs = get_dwarf_regstr(regn, machine);
 283         if (!regs) {
 284                 /* This should be a bug in DWARF or this tool */
 285                 pr_warning("Mapping for the register number %u "
 286                            "missing on this architecture.\n", regn);
 287                 return -ENOTSUP;
 288         }
 289
 290         tvar->value = strdup(regs);
 291         if (tvar->value == NULL)
 292                 return -ENOMEM;
 293
 294         if (ref) {
 295                 tvar->ref = alloc_trace_arg_ref((long)offs);
 296                 if (tvar->ref == NULL)
 297                         return -ENOMEM;
 298         }
 299         return ret2;
 300 }
 301
 302 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 303
 304 static int convert_variable_type(Dwarf_Die *vr_die,
 305                                  struct probe_trace_arg *tvar,
 306                                  const char *cast, bool user_access)
 307 {
 308         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 309         Dwarf_Die type;
 310         char buf[16];
 311         char sbuf[STRERR_BUFSIZE];
 312         int bsize, boffs, total;
 313         int ret;
 314         char prefix;
 315
 316         /* TODO: check all types */
 317         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "ustring") &&
 318             strcmp(cast, "x") != 0 &&
 319             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
 320                 /* Non string type is OK */
 321                 /* and respect signedness/hexadecimal cast */
 322                 tvar->type = strdup(cast);
 323                 return (tvar->type == NULL) ? -ENOMEM : 0;
 324         }
 325
 326         bsize = dwarf_bitsize(vr_die);
 327         if (bsize > 0) {
 328                 /* This is a bitfield */
 329                 boffs = dwarf_bitoffset(vr_die);
 330                 total = dwarf_bytesize(vr_die);
 331                 if (boffs < 0 || total < 0)
 332                         return -ENOENT;
 333                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 334                                 BYTES_TO_BITS(total));
 335                 goto formatted;
 336         }
 337
 338         if (die_get_real_type(vr_die, &type) == NULL) {
 339                 pr_warning("Failed to get a type information of %s.\n",
 340                            dwarf_diename(vr_die));
 341                 return -ENOENT;
 342         }
 343
 344         pr_debug("%s type is %s.\n",
 345                  dwarf_diename(vr_die), dwarf_diename(&type));
 346
 347         if (cast && (!strcmp(cast, "string") || !strcmp(cast, "ustring"))) {
 348                 /* String type */
 349                 ret = dwarf_tag(&type);
 350                 if (ret != DW_TAG_pointer_type &&
 351                     ret != DW_TAG_array_type) {
 352                         pr_warning("Failed to cast into string: "
 353                                    "%s(%s) is not a pointer nor array.\n",
 354                                    dwarf_diename(vr_die), dwarf_diename(&type));
 355                         return -EINVAL;
 356                 }
 357                 if (die_get_real_type(&type, &type) == NULL) {
 358                         pr_warning("Failed to get a type"
 359                                    " information.\n");
 360                         return -ENOENT;
 361                 }
 362                 if (ret == DW_TAG_pointer_type) {
 363                         while (*ref_ptr)
 364                                 ref_ptr = &(*ref_ptr)->next;
 365                         /* Add new reference with offset +0 */
 366                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 367                         if (*ref_ptr == NULL) {
 368                                 pr_warning("Out of memory error\n");
 369                                 return -ENOMEM;
 370                         }
 371                         (*ref_ptr)->user_access = user_access;
 372                 }
 373                 if (!die_compare_name(&type, "char") &&
 374                     !die_compare_name(&type, "unsigned char")) {
 375                         pr_warning("Failed to cast into string: "
 376                                    "%s is not (unsigned) char *.\n",
 377                                    dwarf_diename(vr_die));
 378                         return -EINVAL;
 379                 }
 380                 tvar->type = strdup(cast);
 381                 return (tvar->type == NULL) ? -ENOMEM : 0;
 382         }
 383
 384         if (cast && (strcmp(cast, "u") == 0))
 385                 prefix = 'u';
 386         else if (cast && (strcmp(cast, "s") == 0))
 387                 prefix = 's';
 388         else if (cast && (strcmp(cast, "x") == 0) &&
 389                  probe_type_is_available(PROBE_TYPE_X))
 390                 prefix = 'x';
 391         else
 392                 prefix = die_is_signed_type(&type) ? 's' :
 393                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
 394
 395         ret = dwarf_bytesize(&type);
 396         if (ret <= 0)
 397                 /* No size ... try to use default type */
 398                 return 0;
 399         ret = BYTES_TO_BITS(ret);
 400
 401         /* Check the bitwidth */
 402         if (ret > MAX_BASIC_TYPE_BITS) {
 403                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 404                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 405                 ret = MAX_BASIC_TYPE_BITS;
 406         }
 407         ret = snprintf(buf, 16, "%c%d", prefix, ret);
 408
 409 formatted:
 410         if (ret < 0 || ret >= 16) {
 411                 if (ret >= 16)
 412                         ret = -E2BIG;
 413                 pr_warning("Failed to convert variable type: %s\n",
 414                            str_error_r(-ret, sbuf, sizeof(sbuf)));
 415                 return ret;
 416         }
 417         tvar->type = strdup(buf);
 418         if (tvar->type == NULL)
 419                 return -ENOMEM;
 420         return 0;
 421 }
 422
 423 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 424                                     struct perf_probe_arg_field *field,
 425                                     struct probe_trace_arg_ref **ref_ptr,
 426                                     Dwarf_Die *die_mem, bool user_access)
 427 {
 428         struct probe_trace_arg_ref *ref = *ref_ptr;
 429         Dwarf_Die type;
 430         Dwarf_Word offs;
 431         int ret, tag;
 432
 433         pr_debug("converting %s in %s\n", field->name, varname);
 434         if (die_get_real_type(vr_die, &type) == NULL) {
 435                 pr_warning("Failed to get the type of %s.\n", varname);
 436                 return -ENOENT;
 437         }
 438         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
 439                   (unsigned)dwarf_dieoffset(&type));
 440         tag = dwarf_tag(&type);
 441
 442         if (field->name[0] == '[' &&
 443             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 444                 /* Save original type for next field or type */
 445                 memcpy(die_mem, &type, sizeof(*die_mem));
 446                 /* Get the type of this array */
 447                 if (die_get_real_type(&type, &type) == NULL) {
 448                         pr_warning("Failed to get the type of %s.\n", varname);
 449                         return -ENOENT;
 450                 }
 451                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
 452                          (unsigned)dwarf_dieoffset(&type));
 453                 if (tag == DW_TAG_pointer_type) {
 454                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 455                         if (ref == NULL)
 456                                 return -ENOMEM;
 457                         if (*ref_ptr)
 458                                 (*ref_ptr)->next = ref;
 459                         else
 460                                 *ref_ptr = ref;
 461                 }
 462                 ref->offset += dwarf_bytesize(&type) * field->index;
 463                 ref->user_access = user_access;
 464                 goto next;
 465         } else if (tag == DW_TAG_pointer_type) {
 466                 /* Check the pointer and dereference */
 467                 if (!field->ref) {
 468                         pr_err("Semantic error: %s must be referred by '->'\n",
 469                                field->name);
 470                         return -EINVAL;
 471                 }
 472                 /* Get the type pointed by this pointer */
 473                 if (die_get_real_type(&type, &type) == NULL) {
 474                         pr_warning("Failed to get the type of %s.\n", varname);
 475                         return -ENOENT;
 476                 }
 477                 /* Verify it is a data structure  */
 478                 tag = dwarf_tag(&type);
 479                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 480                         pr_warning("%s is not a data structure nor a union.\n",
 481                                    varname);
 482                         return -EINVAL;
 483                 }
 484
 485                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 486                 if (ref == NULL)
 487                         return -ENOMEM;
 488                 if (*ref_ptr)
 489                         (*ref_ptr)->next = ref;
 490                 else
 491                         *ref_ptr = ref;
 492         } else {
 493                 /* Verify it is a data structure  */
 494                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 495                         pr_warning("%s is not a data structure nor a union.\n",
 496                                    varname);
 497                         return -EINVAL;
 498                 }
 499                 if (field->name[0] == '[') {
 500                         pr_err("Semantic error: %s is not a pointer"
 501                                " nor array.\n", varname);
 502                         return -EINVAL;
 503                 }
 504                 /* While processing unnamed field, we don't care about this */
 505                 if (field->ref && dwarf_diename(vr_die)) {
 506                         pr_err("Semantic error: %s must be referred by '.'\n",
 507                                field->name);
 508                         return -EINVAL;
 509                 }
 510                 if (!ref) {
 511                         pr_warning("Structure on a register is not "
 512                                    "supported yet.\n");
 513                         return -ENOTSUP;
 514                 }
 515         }
 516
 517         if (die_find_member(&type, field->name, die_mem) == NULL) {
 518                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 519                            dwarf_diename(&type), field->name);
 520                 return -EINVAL;
 521         }
 522
 523         /* Get the offset of the field */
 524         if (tag == DW_TAG_union_type) {
 525                 offs = 0;
 526         } else {
 527                 ret = die_get_data_member_location(die_mem, &offs);
 528                 if (ret < 0) {
 529                         pr_warning("Failed to get the offset of %s.\n",
 530                                    field->name);
 531                         return ret;
 532                 }
 533         }
 534         ref->offset += (long)offs;
 535         ref->user_access = user_access;
 536
 537         /* If this member is unnamed, we need to reuse this field */
 538         if (!dwarf_diename(die_mem))
 539                 return convert_variable_fields(die_mem, varname, field,
 540                                                 &ref, die_mem, user_access);
 541
 542 next:
 543         /* Converting next field */
 544         if (field->next)
 545                 return convert_variable_fields(die_mem, field->name,
 546                                 field->next, &ref, die_mem, user_access);
 547         else
 548                 return 0;
 549 }
 550
 551 static void print_var_not_found(const char *varname)
 552 {
 553         pr_err("Failed to find the location of the '%s' variable at this address.\n"
 554                " Perhaps it has been optimized out.\n"
 555                " Use -V with the --range option to show '%s' location range.\n",
 556                 varname, varname);
 557 }
 558
 559 /* Show a variables in kprobe event format */
 560 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 561 {
 562         Dwarf_Die die_mem;
 563         int ret;
 564
 565         pr_debug("Converting variable %s into trace event.\n",
 566                  dwarf_diename(vr_die));
 567
 568         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 569                                         &pf->sp_die, pf->machine, pf->tvar);
 570         if (ret == -ENOENT && pf->skip_empty_arg)
 571                 /* This can be found in other place. skip it */
 572                 return 0;
 573         if (ret == -ENOENT || ret == -EINVAL) {
 574                 print_var_not_found(pf->pvar->var);
 575         } else if (ret == -ENOTSUP)
 576                 pr_err("Sorry, we don't support this variable location yet.\n");
 577         else if (ret == 0 && pf->pvar->field) {
 578                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 579                                               pf->pvar->field, &pf->tvar->ref,
 580                                               &die_mem, pf->pvar->user_access);
 581                 vr_die = &die_mem;
 582         }
 583         if (ret == 0)
 584                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type,
 585                                             pf->pvar->user_access);
 586         /* *expr will be cached in libdw. Don't free it. */
 587         return ret;
 588 }
 589
 590 /* Find a variable in a scope DIE */
 591 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 592 {
 593         Dwarf_Die vr_die;
 594         char *buf, *ptr;
 595         int ret = 0;
 596
 597         /* Copy raw parameters */
 598         if (!is_c_varname(pf->pvar->var))
 599                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
 600
 601         if (pf->pvar->name)
 602                 pf->tvar->name = strdup(pf->pvar->name);
 603         else {
 604                 buf = synthesize_perf_probe_arg(pf->pvar);
 605                 if (!buf)
 606                         return -ENOMEM;
 607                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 608                 if (ptr)
 609                         *ptr = '_';
 610                 pf->tvar->name = buf;
 611         }
 612         if (pf->tvar->name == NULL)
 613                 return -ENOMEM;
 614
 615         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 616         /* Search child die for local variables and parameters. */
 617         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 618                 /* Search again in global variables */
 619                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 620                                                 0, &vr_die)) {
 621                         if (pf->skip_empty_arg)
 622                                 return 0;
 623                         pr_warning("Failed to find '%s' in this function.\n",
 624                                    pf->pvar->var);
 625                         ret = -ENOENT;
 626                 }
 627         }
 628         if (ret >= 0)
 629                 ret = convert_variable(&vr_die, pf);
 630
 631         return ret;
 632 }
 633
 634 /* Convert subprogram DIE to trace point */
 635 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 636                                   Dwarf_Addr paddr, bool retprobe,
 637                                   const char *function,
 638                                   struct probe_trace_point *tp)
 639 {
 640         Dwarf_Addr eaddr;
 641         GElf_Sym sym;
 642         const char *symbol;
 643
 644         /* Verify the address is correct */
 645         if (!dwarf_haspc(sp_die, paddr)) {
 646                 pr_warning("Specified offset is out of %s\n",
 647                            dwarf_diename(sp_die));
 648                 return -EINVAL;
 649         }
 650
 651         if (dwarf_entrypc(sp_die, &eaddr) == 0) {
 652                 /* If the DIE has entrypc, use it. */
 653                 symbol = dwarf_diename(sp_die);
 654         } else {
 655                 /* Try to get actual symbol name and address from symtab */
 656                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 657                 eaddr = sym.st_value;
 658         }
 659         if (!symbol) {
 660                 pr_warning("Failed to find symbol at 0x%lx\n",
 661                            (unsigned long)paddr);
 662                 return -ENOENT;
 663         }
 664
 665         tp->offset = (unsigned long)(paddr - eaddr);
 666         tp->address = (unsigned long)paddr;
 667         tp->symbol = strdup(symbol);
 668         if (!tp->symbol)
 669                 return -ENOMEM;
 670
 671         /* Return probe must be on the head of a subprogram */
 672         if (retprobe) {
 673                 if (eaddr != paddr) {
 674                         pr_warning("Failed to find \"%s%%return\",\n"
 675                                    " because %s is an inlined function and"
 676                                    " has no return point.\n", function,
 677                                    function);
 678                         return -EINVAL;
 679                 }
 680                 tp->retprobe = true;
 681         }
 682
 683         return 0;
 684 }
 685
 686 /* Call probe_finder callback with scope DIE */
 687 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 688 {
 689         Dwarf_Attribute fb_attr;
 690         Dwarf_Frame *frame = NULL;
 691         size_t nops;
 692         int ret;
 693
 694         if (!sc_die) {
 695                 pr_err("Caller must pass a scope DIE. Program error.\n");
 696                 return -EINVAL;
 697         }
 698
 699         /* If not a real subprogram, find a real one */
 700         if (!die_is_func_def(sc_die)) {
 701                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 702                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 703                                 pr_warning("Ignoring tail call from %s\n",
 704                                                 dwarf_diename(&pf->sp_die));
 705                                 return 0;
 706                         } else {
 707                                 pr_warning("Failed to find probe point in any "
 708                                            "functions.\n");
 709                                 return -ENOENT;
 710                         }
 711                 }
 712         } else
 713                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 714
 715         /* Get the frame base attribute/ops from subprogram */
 716         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 717         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 718         if (ret <= 0 || nops == 0) {
 719                 pf->fb_ops = NULL;
 720 #if _ELFUTILS_PREREQ(0, 142)
 721         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 722                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
 723                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
 724                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
 725                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 726                         pr_warning("Failed to get call frame on 0x%jx\n",
 727                                    (uintmax_t)pf->addr);
 728                         free(frame);
 729                         return -ENOENT;
 730                 }
 731 #endif
 732         }
 733
 734         /* Call finder's callback handler */
 735         ret = pf->callback(sc_die, pf);
 736
 737         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
 738         free(frame);
 739         pf->fb_ops = NULL;
 740
 741         return ret;
 742 }
 743
 744 struct find_scope_param {
 745         const char *function;
 746         const char *file;
 747         int line;
 748         int diff;
 749         Dwarf_Die *die_mem;
 750         bool found;
 751 };
 752
 753 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 754 {
 755         struct find_scope_param *fsp = data;
 756         const char *file;
 757         int lno;
 758
 759         /* Skip if declared file name does not match */
 760         if (fsp->file) {
 761                 file = dwarf_decl_file(fn_die);
 762                 if (!file || strcmp(fsp->file, file) != 0)
 763                         return 0;
 764         }
 765         /* If the function name is given, that's what user expects */
 766         if (fsp->function) {
 767                 if (die_match_name(fn_die, fsp->function)) {
 768                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 769                         fsp->found = true;
 770                         return 1;
 771                 }
 772         } else {
 773                 /* With the line number, find the nearest declared DIE */
 774                 dwarf_decl_line(fn_die, &lno);
 775                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 776                         /* Keep a candidate and continue */
 777                         fsp->diff = fsp->line - lno;
 778                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 779                         fsp->found = true;
 780                 }
 781         }
 782         return 0;
 783 }
 784
 785 /* Return innermost DIE */
 786 static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data)
 787 {
 788         struct find_scope_param *fsp = data;
 789
 790         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 791         fsp->found = true;
 792         return 1;
 793 }
 794
 795 /* Find an appropriate scope fits to given conditions */
 796 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 797 {
 798         struct find_scope_param fsp = {
 799                 .function = pf->pev->point.function,
 800                 .file = pf->fname,
 801                 .line = pf->lno,
 802                 .diff = INT_MAX,
 803                 .die_mem = die_mem,
 804                 .found = false,
 805         };
 806         int ret;
 807
 808         ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb,
 809                                    &fsp);
 810         if (!ret && !fsp.found)
 811                 cu_walk_functions_at(&pf->cu_die, pf->addr,
 812                                      find_inner_scope_cb, &fsp);
 813
 814         return fsp.found ? die_mem : NULL;
 815 }
 816
 817 static int verify_representive_line(struct probe_finder *pf, const char *fname,
 818                                 int lineno, Dwarf_Addr addr)
 819 {
 820         const char *__fname, *__func = NULL;
 821         Dwarf_Die die_mem;
 822         int __lineno;
 823
 824         /* Verify line number and address by reverse search */
 825         if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0)
 826                 return 0;
 827
 828         pr_debug2("Reversed line: %s:%d\n", __fname, __lineno);
 829         if (strcmp(fname, __fname) || lineno == __lineno)
 830                 return 0;
 831
 832         pr_warning("This line is sharing the address with other lines.\n");
 833
 834         if (pf->pev->point.function) {
 835                 /* Find best match function name and lines */
 836                 pf->addr = addr;
 837                 if (find_best_scope(pf, &die_mem)
 838                     && die_match_name(&die_mem, pf->pev->point.function)
 839                     && dwarf_decl_line(&die_mem, &lineno) == 0) {
 840                         __func = dwarf_diename(&die_mem);
 841                         __lineno -= lineno;
 842                 }
 843         }
 844         pr_warning("Please try to probe at %s:%d instead.\n",
 845                    __func ? : __fname, __lineno);
 846
 847         return -ENOENT;
 848 }
 849
 850 static int probe_point_line_walker(const char *fname, int lineno,
 851                                    Dwarf_Addr addr, void *data)
 852 {
 853         struct probe_finder *pf = data;
 854         Dwarf_Die *sc_die, die_mem;
 855         int ret;
 856
 857         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 858                 return 0;
 859
 860         if (verify_representive_line(pf, fname, lineno, addr))
 861                 return -ENOENT;
 862
 863         pf->addr = addr;
 864         sc_die = find_best_scope(pf, &die_mem);
 865         if (!sc_die) {
 866                 pr_warning("Failed to find scope of probe point.\n");
 867                 return -ENOENT;
 868         }
 869
 870         ret = call_probe_finder(sc_die, pf);
 871
 872         /* Continue if no error, because the line will be in inline function */
 873         return ret < 0 ? ret : 0;
 874 }
 875
 876 /* Find probe point from its line number */
 877 static int find_probe_point_by_line(struct probe_finder *pf)
 878 {
 879         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 880 }
 881
 882 /* Find lines which match lazy pattern */
 883 static int find_lazy_match_lines(struct intlist *list,
 884                                  const char *fname, const char *pat)
 885 {
 886         FILE *fp;
 887         char *line = NULL;
 888         size_t line_len;
 889         ssize_t len;
 890         int count = 0, linenum = 1;
 891         char sbuf[STRERR_BUFSIZE];
 892
 893         fp = fopen(fname, "r");
 894         if (!fp) {
 895                 pr_warning("Failed to open %s: %s\n", fname,
 896                            str_error_r(errno, sbuf, sizeof(sbuf)));
 897                 return -errno;
 898         }
 899
 900         while ((len = getline(&line, &line_len, fp)) > 0) {
 901
 902                 if (line[len - 1] == '\n')
 903                         line[len - 1] = '\0';
 904
 905                 if (strlazymatch(line, pat)) {
 906                         intlist__add(list, linenum);
 907                         count++;
 908                 }
 909                 linenum++;
 910         }
 911
 912         if (ferror(fp))
 913                 count = -errno;
 914         free(line);
 915         fclose(fp);
 916
 917         if (count == 0)
 918                 pr_debug("No matched lines found in %s.\n", fname);
 919         return count;
 920 }
 921
 922 static int probe_point_lazy_walker(const char *fname, int lineno,
 923                                    Dwarf_Addr addr, void *data)
 924 {
 925         struct probe_finder *pf = data;
 926         Dwarf_Die *sc_die, die_mem;
 927         int ret;
 928
 929         if (!intlist__has_entry(pf->lcache, lineno) ||
 930             strtailcmp(fname, pf->fname) != 0)
 931                 return 0;
 932
 933         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 934                  lineno, (unsigned long long)addr);
 935         pf->addr = addr;
 936         pf->lno = lineno;
 937         sc_die = find_best_scope(pf, &die_mem);
 938         if (!sc_die) {
 939                 pr_warning("Failed to find scope of probe point.\n");
 940                 return -ENOENT;
 941         }
 942
 943         ret = call_probe_finder(sc_die, pf);
 944
 945         /*
 946          * Continue if no error, because the lazy pattern will match
 947          * to other lines
 948          */
 949         return ret < 0 ? ret : 0;
 950 }
 951
 952 /* Find probe points from lazy pattern  */
 953 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 954 {
 955         struct build_id bid;
 956         char sbuild_id[SBUILD_ID_SIZE] = "";
 957         int ret = 0;
 958         char *fpath;
 959
 960         if (intlist__empty(pf->lcache)) {
 961                 const char *comp_dir;
 962
 963                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 964                 if (pf->dbg->build_id) {
 965                         build_id__init(&bid, pf->dbg->build_id, BUILD_ID_SIZE);
 966                         build_id__sprintf(&bid, sbuild_id);
 967                 }
 968                 ret = find_source_path(pf->fname, sbuild_id, comp_dir, &fpath);
 969                 if (ret < 0) {
 970                         pr_warning("Failed to find source file path.\n");
 971                         return ret;
 972                 }
 973
 974                 /* Matching lazy line pattern */
 975                 ret = find_lazy_match_lines(pf->lcache, fpath,
 976                                             pf->pev->point.lazy_line);
 977                 free(fpath);
 978                 if (ret <= 0)
 979                         return ret;
 980         }
 981
 982         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 983 }
 984
 985 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
 986 {
 987         struct perf_probe_point *pp = &pf->pev->point;
 988
 989         /* Not uprobe? */
 990         if (!pf->pev->uprobes)
 991                 return;
 992
 993         /* Compiled with optimization? */
 994         if (die_is_optimized_target(&pf->cu_die))
 995                 return;
 996
 997         /* Don't know entrypc? */
 998         if (!pf->addr)
 999                 return;
1000
1001         /* Only FUNC and FUNC@SRC are eligible. */
1002         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
1003             pp->offset || pp->abs_address)
1004                 return;
1005
1006         /* Not interested in func parameter? */
1007         if (!perf_probe_with_var(pf->pev))
1008                 return;
1009
1010         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
1011                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
1012                 pf->addr);
1013
1014         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
1015 }
1016
1017 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
1018 {
1019         struct probe_finder *pf = data;
1020         struct perf_probe_point *pp = &pf->pev->point;
1021         Dwarf_Addr addr;
1022         int ret;
1023
1024         if (pp->lazy_line)
1025                 ret = find_probe_point_lazy(in_die, pf);
1026         else {
1027                 /* Get probe address */
1028                 if (die_entrypc(in_die, &addr) != 0) {
1029                         pr_warning("Failed to get entry address of %s.\n",
1030                                    dwarf_diename(in_die));
1031                         return -ENOENT;
1032                 }
1033                 if (addr == 0) {
1034                         pr_debug("%s has no valid entry address. skipped.\n",
1035                                  dwarf_diename(in_die));
1036                         return -ENOENT;
1037                 }
1038                 pf->addr = addr;
1039                 pf->addr += pp->offset;
1040                 pr_debug("found inline addr: 0x%jx\n",
1041                          (uintmax_t)pf->addr);
1042
1043                 ret = call_probe_finder(in_die, pf);
1044         }
1045
1046         return ret;
1047 }
1048
1049 /* Callback parameter with return value for libdw */
1050 struct dwarf_callback_param {
1051         void *data;
1052         int retval;
1053 };
1054
1055 /* Search function from function name */
1056 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
1057 {
1058         struct dwarf_callback_param *param = data;
1059         struct probe_finder *pf = param->data;
1060         struct perf_probe_point *pp = &pf->pev->point;
1061
1062         /* Check tag and diename */
1063         if (!die_is_func_def(sp_die) ||
1064             !die_match_name(sp_die, pp->function))
1065                 return DWARF_CB_OK;
1066
1067         /* Check declared file */
1068         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
1069                 return DWARF_CB_OK;
1070
1071         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
1072                  (unsigned long)dwarf_dieoffset(sp_die));
1073         pf->fname = dwarf_decl_file(sp_die);
1074         if (pp->line) { /* Function relative line */
1075                 dwarf_decl_line(sp_die, &pf->lno);
1076                 pf->lno += pp->line;
1077                 param->retval = find_probe_point_by_line(pf);
1078         } else if (die_is_func_instance(sp_die)) {
1079                 /* Instances always have the entry address */
1080                 die_entrypc(sp_die, &pf->addr);
1081                 /* But in some case the entry address is 0 */
1082                 if (pf->addr == 0) {
1083                         pr_debug("%s has no entry PC. Skipped\n",
1084                                  dwarf_diename(sp_die));
1085                         param->retval = 0;
1086                 /* Real function */
1087                 } else if (pp->lazy_line)
1088                         param->retval = find_probe_point_lazy(sp_die, pf);
1089                 else {
1090                         skip_prologue(sp_die, pf);
1091                         pf->addr += pp->offset;
1092                         /* TODO: Check the address in this function */
1093                         param->retval = call_probe_finder(sp_die, pf);
1094                 }
1095         } else if (!probe_conf.no_inlines) {
1096                 /* Inlined function: search instances */
1097                 param->retval = die_walk_instances(sp_die,
1098                                         probe_point_inline_cb, (void *)pf);
1099                 /* This could be a non-existed inline definition */
1100                 if (param->retval == -ENOENT)
1101                         param->retval = 0;
1102         }
1103
1104         /* We need to find other candidates */
1105         if (strisglob(pp->function) && param->retval >= 0) {
1106                 param->retval = 0;      /* We have to clear the result */
1107                 return DWARF_CB_OK;
1108         }
1109
1110         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1111 }
1112
1113 static int find_probe_point_by_func(struct probe_finder *pf)
1114 {
1115         struct dwarf_callback_param _param = {.data = (void *)pf,
1116                                               .retval = 0};
1117         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1118         return _param.retval;
1119 }
1120
1121 struct pubname_callback_param {
1122         char *function;
1123         char *file;
1124         Dwarf_Die *cu_die;
1125         Dwarf_Die *sp_die;
1126         int found;
1127 };
1128
1129 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1130 {
1131         struct pubname_callback_param *param = data;
1132
1133         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1134                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1135                         return DWARF_CB_OK;
1136
1137                 if (die_match_name(param->sp_die, param->function)) {
1138                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1139                                 return DWARF_CB_OK;
1140
1141                         if (param->file &&
1142                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1143                                 return DWARF_CB_OK;
1144
1145                         param->found = 1;
1146                         return DWARF_CB_ABORT;
1147                 }
1148         }
1149
1150         return DWARF_CB_OK;
1151 }
1152
1153 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1154                                   struct probe_finder *pf)
1155 {
1156         struct perf_probe_point *pp = &pf->pev->point;
1157         Dwarf_Off off, noff;
1158         size_t cuhl;
1159         Dwarf_Die *diep;
1160         int ret = 0;
1161
1162         off = 0;
1163         pf->lcache = intlist__new(NULL);
1164         if (!pf->lcache)
1165                 return -ENOMEM;
1166
1167         /* Fastpath: lookup by function name from .debug_pubnames section */
1168         if (pp->function && !strisglob(pp->function)) {
1169                 struct pubname_callback_param pubname_param = {
1170                         .function = pp->function,
1171                         .file     = pp->file,
1172                         .cu_die   = &pf->cu_die,
1173                         .sp_die   = &pf->sp_die,
1174                         .found    = 0,
1175                 };
1176                 struct dwarf_callback_param probe_param = {
1177                         .data = pf,
1178                 };
1179
1180                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1181                                   &pubname_param, 0);
1182                 if (pubname_param.found) {
1183                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1184                         if (ret)
1185                                 goto found;
1186                 }
1187         }
1188
1189         /* Loop on CUs (Compilation Unit) */
1190         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1191                 /* Get the DIE(Debugging Information Entry) of this CU */
1192                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1193                 if (!diep) {
1194                         off = noff;
1195                         continue;
1196                 }
1197
1198                 /* Check if target file is included. */
1199                 if (pp->file)
1200                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1201                 else
1202                         pf->fname = NULL;
1203
1204                 if (!pp->file || pf->fname) {
1205                         if (pp->function)
1206                                 ret = find_probe_point_by_func(pf);
1207                         else if (pp->lazy_line)
1208                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1209                         else {
1210                                 pf->lno = pp->line;
1211                                 ret = find_probe_point_by_line(pf);
1212                         }
1213                         if (ret < 0)
1214                                 break;
1215                 }
1216                 off = noff;
1217         }
1218
1219 found:
1220         intlist__delete(pf->lcache);
1221         pf->lcache = NULL;
1222
1223         return ret;
1224 }
1225
1226 /* Find probe points from debuginfo */
1227 static int debuginfo__find_probes(struct debuginfo *dbg,
1228                                   struct probe_finder *pf)
1229 {
1230         int ret = 0;
1231         Elf *elf;
1232         GElf_Ehdr ehdr;
1233
1234         if (pf->cfi_eh || pf->cfi_dbg)
1235                 return debuginfo__find_probe_location(dbg, pf);
1236
1237         /* Get the call frame information from this dwarf */
1238         elf = dwarf_getelf(dbg->dbg);
1239         if (elf == NULL)
1240                 return -EINVAL;
1241
1242         if (gelf_getehdr(elf, &ehdr) == NULL)
1243                 return -EINVAL;
1244
1245         pf->machine = ehdr.e_machine;
1246
1247 #if _ELFUTILS_PREREQ(0, 142)
1248         do {
1249                 GElf_Shdr shdr;
1250
1251                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1252                     shdr.sh_type == SHT_PROGBITS)
1253                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1254
1255                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1256         } while (0);
1257 #endif
1258
1259         ret = debuginfo__find_probe_location(dbg, pf);
1260         return ret;
1261 }
1262
1263 struct local_vars_finder {
1264         struct probe_finder *pf;
1265         struct perf_probe_arg *args;
1266         bool vars;
1267         int max_args;
1268         int nargs;
1269         int ret;
1270 };
1271
1272 /* Collect available variables in this scope */
1273 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1274 {
1275         struct local_vars_finder *vf = data;
1276         struct probe_finder *pf = vf->pf;
1277         int tag;
1278
1279         tag = dwarf_tag(die_mem);
1280         if (tag == DW_TAG_formal_parameter ||
1281             (tag == DW_TAG_variable && vf->vars)) {
1282                 if (convert_variable_location(die_mem, vf->pf->addr,
1283                                               vf->pf->fb_ops, &pf->sp_die,
1284                                               pf->machine, NULL) == 0) {
1285                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1286                         if (vf->args[vf->nargs].var == NULL) {
1287                                 vf->ret = -ENOMEM;
1288                                 return DIE_FIND_CB_END;
1289                         }
1290                         pr_debug(" %s", vf->args[vf->nargs].var);
1291                         vf->nargs++;
1292                 }
1293         }
1294
1295         if (dwarf_haspc(die_mem, vf->pf->addr))
1296                 return DIE_FIND_CB_CONTINUE;
1297         else
1298                 return DIE_FIND_CB_SIBLING;
1299 }
1300
1301 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1302                              struct perf_probe_arg *args)
1303 {
1304         Dwarf_Die die_mem;
1305         int i;
1306         int n = 0;
1307         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1308                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1309
1310         for (i = 0; i < pf->pev->nargs; i++) {
1311                 /* var never be NULL */
1312                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1313                         vf.vars = true;
1314                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1315                         /* Copy normal argument */
1316                         args[n] = pf->pev->args[i];
1317                         n++;
1318                         continue;
1319                 }
1320                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1321                 vf.nargs = n;
1322                 /* Special local variables */
1323                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1324                                &die_mem);
1325                 pr_debug(" (%d)\n", vf.nargs - n);
1326                 if (vf.ret < 0)
1327                         return vf.ret;
1328                 n = vf.nargs;
1329         }
1330         return n;
1331 }
1332
1333 static bool trace_event_finder_overlap(struct trace_event_finder *tf)
1334 {
1335         int i;
1336
1337         for (i = 0; i < tf->ntevs; i++) {
1338                 if (tf->pf.addr == tf->tevs[i].point.address)
1339                         return true;
1340         }
1341         return false;
1342 }
1343
1344 /* Add a found probe point into trace event list */
1345 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1346 {
1347         struct trace_event_finder *tf =
1348                         container_of(pf, struct trace_event_finder, pf);
1349         struct perf_probe_point *pp = &pf->pev->point;
1350         struct probe_trace_event *tev;
1351         struct perf_probe_arg *args = NULL;
1352         int ret, i;
1353
1354         /*
1355          * For some reason (e.g. different column assigned to same address)
1356          * This callback can be called with the address which already passed.
1357          * Ignore it first.
1358          */
1359         if (trace_event_finder_overlap(tf))
1360                 return 0;
1361
1362         /* Check number of tevs */
1363         if (tf->ntevs == tf->max_tevs) {
1364                 pr_warning("Too many( > %d) probe point found.\n",
1365                            tf->max_tevs);
1366                 return -ERANGE;
1367         }
1368         tev = &tf->tevs[tf->ntevs++];
1369
1370         /* Trace point should be converted from subprogram DIE */
1371         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1372                                      pp->retprobe, pp->function, &tev->point);
1373         if (ret < 0)
1374                 goto end;
1375
1376         tev->point.realname = strdup(dwarf_diename(sc_die));
1377         if (!tev->point.realname) {
1378                 ret = -ENOMEM;
1379                 goto end;
1380         }
1381
1382         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1383                  tev->point.offset);
1384
1385         /* Expand special probe argument if exist */
1386         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1387         if (args == NULL) {
1388                 ret = -ENOMEM;
1389                 goto end;
1390         }
1391
1392         ret = expand_probe_args(sc_die, pf, args);
1393         if (ret < 0)
1394                 goto end;
1395
1396         tev->nargs = ret;
1397         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1398         if (tev->args == NULL) {
1399                 ret = -ENOMEM;
1400                 goto end;
1401         }
1402
1403         /* Find each argument */
1404         for (i = 0; i < tev->nargs; i++) {
1405                 pf->pvar = &args[i];
1406                 pf->tvar = &tev->args[i];
1407                 /* Variable should be found from scope DIE */
1408                 ret = find_variable(sc_die, pf);
1409                 if (ret != 0)
1410                         break;
1411         }
1412
1413 end:
1414         if (ret) {
1415                 clear_probe_trace_event(tev);
1416                 tf->ntevs--;
1417         }
1418         free(args);
1419         return ret;
1420 }
1421
1422 static int fill_empty_trace_arg(struct perf_probe_event *pev,
1423                                 struct probe_trace_event *tevs, int ntevs)
1424 {
1425         char **valp;
1426         char *type;
1427         int i, j, ret;
1428
1429         if (!ntevs)
1430                 return -ENOENT;
1431
1432         for (i = 0; i < pev->nargs; i++) {
1433                 type = NULL;
1434                 for (j = 0; j < ntevs; j++) {
1435                         if (tevs[j].args[i].value) {
1436                                 type = tevs[j].args[i].type;
1437                                 break;
1438                         }
1439                 }
1440                 if (j == ntevs) {
1441                         print_var_not_found(pev->args[i].var);
1442                         return -ENOENT;
1443                 }
1444                 for (j = 0; j < ntevs; j++) {
1445                         valp = &tevs[j].args[i].value;
1446                         if (*valp)
1447                                 continue;
1448
1449                         ret = asprintf(valp, "\\%lx", probe_conf.magic_num);
1450                         if (ret < 0)
1451                                 return -ENOMEM;
1452                         /* Note that type can be NULL */
1453                         if (type) {
1454                                 tevs[j].args[i].type = strdup(type);
1455                                 if (!tevs[j].args[i].type)
1456                                         return -ENOMEM;
1457                         }
1458                 }
1459         }
1460         return 0;
1461 }
1462
1463 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1464 int debuginfo__find_trace_events(struct debuginfo *dbg,
1465                                  struct perf_probe_event *pev,
1466                                  struct probe_trace_event **tevs)
1467 {
1468         struct trace_event_finder tf = {
1469                         .pf = {.pev = pev, .dbg = dbg, .callback = add_probe_trace_event},
1470                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1471         int ret, i;
1472
1473         /* Allocate result tevs array */
1474         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1475         if (*tevs == NULL)
1476                 return -ENOMEM;
1477
1478         tf.tevs = *tevs;
1479         tf.ntevs = 0;
1480
1481         if (pev->nargs != 0 && immediate_value_is_supported())
1482                 tf.pf.skip_empty_arg = true;
1483
1484         ret = debuginfo__find_probes(dbg, &tf.pf);
1485         if (ret >= 0 && tf.pf.skip_empty_arg)
1486                 ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs);
1487
1488         if (ret < 0 || tf.ntevs == 0) {
1489                 for (i = 0; i < tf.ntevs; i++)
1490                         clear_probe_trace_event(&tf.tevs[i]);
1491                 zfree(tevs);
1492                 return ret;
1493         }
1494
1495         return (ret < 0) ? ret : tf.ntevs;
1496 }
1497
1498 /* Collect available variables in this scope */
1499 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1500 {
1501         struct available_var_finder *af = data;
1502         struct variable_list *vl;
1503         struct strbuf buf = STRBUF_INIT;
1504         int tag, ret;
1505
1506         vl = &af->vls[af->nvls - 1];
1507
1508         tag = dwarf_tag(die_mem);
1509         if (tag == DW_TAG_formal_parameter ||
1510             tag == DW_TAG_variable) {
1511                 ret = convert_variable_location(die_mem, af->pf.addr,
1512                                                 af->pf.fb_ops, &af->pf.sp_die,
1513                                                 af->pf.machine, NULL);
1514                 if (ret == 0 || ret == -ERANGE) {
1515                         int ret2;
1516                         bool externs = !af->child;
1517
1518                         if (strbuf_init(&buf, 64) < 0)
1519                                 goto error;
1520
1521                         if (probe_conf.show_location_range) {
1522                                 if (!externs)
1523                                         ret2 = strbuf_add(&buf,
1524                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1525                                 else
1526                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1527                                 if (ret2)
1528                                         goto error;
1529                         }
1530
1531                         ret2 = die_get_varname(die_mem, &buf);
1532
1533                         if (!ret2 && probe_conf.show_location_range &&
1534                                 !externs) {
1535                                 if (strbuf_addch(&buf, '\t') < 0)
1536                                         goto error;
1537                                 ret2 = die_get_var_range(&af->pf.sp_die,
1538                                                         die_mem, &buf);
1539                         }
1540
1541                         pr_debug("Add new var: %s\n", buf.buf);
1542                         if (ret2 == 0) {
1543                                 strlist__add(vl->vars,
1544                                         strbuf_detach(&buf, NULL));
1545                         }
1546                         strbuf_release(&buf);
1547                 }
1548         }
1549
1550         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1551                 return DIE_FIND_CB_CONTINUE;
1552         else
1553                 return DIE_FIND_CB_SIBLING;
1554 error:
1555         strbuf_release(&buf);
1556         pr_debug("Error in strbuf\n");
1557         return DIE_FIND_CB_END;
1558 }
1559
1560 static bool available_var_finder_overlap(struct available_var_finder *af)
1561 {
1562         int i;
1563
1564         for (i = 0; i < af->nvls; i++) {
1565                 if (af->pf.addr == af->vls[i].point.address)
1566                         return true;
1567         }
1568         return false;
1569
1570 }
1571
1572 /* Add a found vars into available variables list */
1573 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1574 {
1575         struct available_var_finder *af =
1576                         container_of(pf, struct available_var_finder, pf);
1577         struct perf_probe_point *pp = &pf->pev->point;
1578         struct variable_list *vl;
1579         Dwarf_Die die_mem;
1580         int ret;
1581
1582         /*
1583          * For some reason (e.g. different column assigned to same address),
1584          * this callback can be called with the address which already passed.
1585          * Ignore it first.
1586          */
1587         if (available_var_finder_overlap(af))
1588                 return 0;
1589
1590         /* Check number of tevs */
1591         if (af->nvls == af->max_vls) {
1592                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1593                 return -ERANGE;
1594         }
1595         vl = &af->vls[af->nvls++];
1596
1597         /* Trace point should be converted from subprogram DIE */
1598         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1599                                      pp->retprobe, pp->function, &vl->point);
1600         if (ret < 0)
1601                 return ret;
1602
1603         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1604                  vl->point.offset);
1605
1606         /* Find local variables */
1607         vl->vars = strlist__new(NULL, NULL);
1608         if (vl->vars == NULL)
1609                 return -ENOMEM;
1610         af->child = true;
1611         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1612
1613         /* Find external variables */
1614         if (!probe_conf.show_ext_vars)
1615                 goto out;
1616         /* Don't need to search child DIE for external vars. */
1617         af->child = false;
1618         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1619
1620 out:
1621         if (strlist__empty(vl->vars)) {
1622                 strlist__delete(vl->vars);
1623                 vl->vars = NULL;
1624         }
1625
1626         return ret;
1627 }
1628
1629 /*
1630  * Find available variables at given probe point
1631  * Return the number of found probe points. Return 0 if there is no
1632  * matched probe point. Return <0 if an error occurs.
1633  */
1634 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1635                                       struct perf_probe_event *pev,
1636                                       struct variable_list **vls)
1637 {
1638         struct available_var_finder af = {
1639                         .pf = {.pev = pev, .dbg = dbg, .callback = add_available_vars},
1640                         .mod = dbg->mod,
1641                         .max_vls = probe_conf.max_probes};
1642         int ret;
1643
1644         /* Allocate result vls array */
1645         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1646         if (*vls == NULL)
1647                 return -ENOMEM;
1648
1649         af.vls = *vls;
1650         af.nvls = 0;
1651
1652         ret = debuginfo__find_probes(dbg, &af.pf);
1653         if (ret < 0) {
1654                 /* Free vlist for error */
1655                 while (af.nvls--) {
1656                         zfree(&af.vls[af.nvls].point.symbol);
1657                         strlist__delete(af.vls[af.nvls].vars);
1658                 }
1659                 zfree(vls);
1660                 return ret;
1661         }
1662
1663         return (ret < 0) ? ret : af.nvls;
1664 }
1665
1666 /* For the kernel module, we need a special code to get a DIE */
1667 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1668                                 bool adjust_offset)
1669 {
1670         int n, i;
1671         Elf32_Word shndx;
1672         Elf_Scn *scn;
1673         Elf *elf;
1674         GElf_Shdr mem, *shdr;
1675         const char *p;
1676
1677         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1678         if (!elf)
1679                 return -EINVAL;
1680
1681         /* Get the number of relocations */
1682         n = dwfl_module_relocations(dbg->mod);
1683         if (n < 0)
1684                 return -ENOENT;
1685         /* Search the relocation related .text section */
1686         for (i = 0; i < n; i++) {
1687                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1688                 if (strcmp(p, ".text") == 0) {
1689                         /* OK, get the section header */
1690                         scn = elf_getscn(elf, shndx);
1691                         if (!scn)
1692                                 return -ENOENT;
1693                         shdr = gelf_getshdr(scn, &mem);
1694                         if (!shdr)
1695                                 return -ENOENT;
1696                         *offs = shdr->sh_addr;
1697                         if (adjust_offset)
1698                                 *offs -= shdr->sh_offset;
1699                 }
1700         }
1701         return 0;
1702 }
1703
1704 /* Reverse search */
1705 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1706                                 struct perf_probe_point *ppt)
1707 {
1708         Dwarf_Die cudie, spdie, indie;
1709         Dwarf_Addr _addr = 0, baseaddr = 0;
1710         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1711         int baseline = 0, lineno = 0, ret = 0;
1712
1713         /* We always need to relocate the address for aranges */
1714         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1715                 addr += baseaddr;
1716         /* Find cu die */
1717         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1718                 pr_warning("Failed to find debug information for address %lx\n",
1719                            addr);
1720                 ret = -EINVAL;
1721                 goto end;
1722         }
1723
1724         /* Find a corresponding line (filename and lineno) */
1725         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1726         /* Don't care whether it failed or not */
1727
1728         /* Find a corresponding function (name, baseline and baseaddr) */
1729         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1730                 /* Get function entry information */
1731                 func = basefunc = dwarf_diename(&spdie);
1732                 if (!func ||
1733                     die_entrypc(&spdie, &baseaddr) != 0 ||
1734                     dwarf_decl_line(&spdie, &baseline) != 0) {
1735                         lineno = 0;
1736                         goto post;
1737                 }
1738
1739                 fname = dwarf_decl_file(&spdie);
1740                 if (addr == (unsigned long)baseaddr) {
1741                         /* Function entry - Relative line number is 0 */
1742                         lineno = baseline;
1743                         goto post;
1744                 }
1745
1746                 /* Track down the inline functions step by step */
1747                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1748                                                 &indie)) {
1749                         /* There is an inline function */
1750                         if (die_entrypc(&indie, &_addr) == 0 &&
1751                             _addr == addr) {
1752                                 /*
1753                                  * addr is at an inline function entry.
1754                                  * In this case, lineno should be the call-site
1755                                  * line number. (overwrite lineinfo)
1756                                  */
1757                                 lineno = die_get_call_lineno(&indie);
1758                                 fname = die_get_call_file(&indie);
1759                                 break;
1760                         } else {
1761                                 /*
1762                                  * addr is in an inline function body.
1763                                  * Since lineno points one of the lines
1764                                  * of the inline function, baseline should
1765                                  * be the entry line of the inline function.
1766                                  */
1767                                 tmp = dwarf_diename(&indie);
1768                                 if (!tmp ||
1769                                     dwarf_decl_line(&indie, &baseline) != 0)
1770                                         break;
1771                                 func = tmp;
1772                                 spdie = indie;
1773                         }
1774                 }
1775                 /* Verify the lineno and baseline are in a same file */
1776                 tmp = dwarf_decl_file(&spdie);
1777                 if (!tmp || strcmp(tmp, fname) != 0)
1778                         lineno = 0;
1779         }
1780
1781 post:
1782         /* Make a relative line number or an offset */
1783         if (lineno)
1784                 ppt->line = lineno - baseline;
1785         else if (basefunc) {
1786                 ppt->offset = addr - (unsigned long)baseaddr;
1787                 func = basefunc;
1788         }
1789
1790         /* Duplicate strings */
1791         if (func) {
1792                 ppt->function = strdup(func);
1793                 if (ppt->function == NULL) {
1794                         ret = -ENOMEM;
1795                         goto end;
1796                 }
1797         }
1798         if (fname) {
1799                 ppt->file = strdup(fname);
1800                 if (ppt->file == NULL) {
1801                         zfree(&ppt->function);
1802                         ret = -ENOMEM;
1803                         goto end;
1804                 }
1805         }
1806 end:
1807         if (ret == 0 && (fname || func))
1808                 ret = 1;        /* Found a point */
1809         return ret;
1810 }
1811
1812 /* Add a line and store the src path */
1813 static int line_range_add_line(const char *src, unsigned int lineno,
1814                                struct line_range *lr)
1815 {
1816         /* Copy source path */
1817         if (!lr->path) {
1818                 lr->path = strdup(src);
1819                 if (lr->path == NULL)
1820                         return -ENOMEM;
1821         }
1822         return intlist__add(lr->line_list, lineno);
1823 }
1824
1825 static int line_range_walk_cb(const char *fname, int lineno,
1826                               Dwarf_Addr addr __maybe_unused,
1827                               void *data)
1828 {
1829         struct line_finder *lf = data;
1830         const char *__fname;
1831         int __lineno;
1832         int err;
1833
1834         if ((strtailcmp(fname, lf->fname) != 0) ||
1835             (lf->lno_s > lineno || lf->lno_e < lineno))
1836                 return 0;
1837
1838         /* Make sure this line can be reversible */
1839         if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0
1840             && (lineno != __lineno || strcmp(fname, __fname)))
1841                 return 0;
1842
1843         err = line_range_add_line(fname, lineno, lf->lr);
1844         if (err < 0 && err != -EEXIST)
1845                 return err;
1846
1847         return 0;
1848 }
1849
1850 /* Find line range from its line number */
1851 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1852 {
1853         int ret;
1854
1855         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1856
1857         /* Update status */
1858         if (ret >= 0)
1859                 if (!intlist__empty(lf->lr->line_list))
1860                         ret = lf->found = 1;
1861                 else
1862                         ret = 0;        /* Lines are not found */
1863         else {
1864                 zfree(&lf->lr->path);
1865         }
1866         return ret;
1867 }
1868
1869 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1870 {
1871         int ret = find_line_range_by_line(in_die, data);
1872
1873         /*
1874          * We have to check all instances of inlined function, because
1875          * some execution paths can be optimized out depends on the
1876          * function argument of instances. However, if an error occurs,
1877          * it should be handled by the caller.
1878          */
1879         return ret < 0 ? ret : 0;
1880 }
1881
1882 /* Search function definition from function name */
1883 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1884 {
1885         struct dwarf_callback_param *param = data;
1886         struct line_finder *lf = param->data;
1887         struct line_range *lr = lf->lr;
1888
1889         /* Check declared file */
1890         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1891                 return DWARF_CB_OK;
1892
1893         if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
1894                 lf->fname = dwarf_decl_file(sp_die);
1895                 dwarf_decl_line(sp_die, &lr->offset);
1896                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1897                 lf->lno_s = lr->offset + lr->start;
1898                 if (lf->lno_s < 0)      /* Overflow */
1899                         lf->lno_s = INT_MAX;
1900                 lf->lno_e = lr->offset + lr->end;
1901                 if (lf->lno_e < 0)      /* Overflow */
1902                         lf->lno_e = INT_MAX;
1903                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1904                 lr->start = lf->lno_s;
1905                 lr->end = lf->lno_e;
1906                 if (!die_is_func_instance(sp_die))
1907                         param->retval = die_walk_instances(sp_die,
1908                                                 line_range_inline_cb, lf);
1909                 else
1910                         param->retval = find_line_range_by_line(sp_die, lf);
1911                 return DWARF_CB_ABORT;
1912         }
1913         return DWARF_CB_OK;
1914 }
1915
1916 static int find_line_range_by_func(struct line_finder *lf)
1917 {
1918         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1919         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1920         return param.retval;
1921 }
1922
1923 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1924 {
1925         struct line_finder lf = {.lr = lr, .found = 0};
1926         int ret = 0;
1927         Dwarf_Off off = 0, noff;
1928         size_t cuhl;
1929         Dwarf_Die *diep;
1930         const char *comp_dir;
1931
1932         /* Fastpath: lookup by function name from .debug_pubnames section */
1933         if (lr->function) {
1934                 struct pubname_callback_param pubname_param = {
1935                         .function = lr->function, .file = lr->file,
1936                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1937                 struct dwarf_callback_param line_range_param = {
1938                         .data = (void *)&lf, .retval = 0};
1939
1940                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1941                                   &pubname_param, 0);
1942                 if (pubname_param.found) {
1943                         line_range_search_cb(&lf.sp_die, &line_range_param);
1944                         if (lf.found)
1945                                 goto found;
1946                 }
1947         }
1948
1949         /* Loop on CUs (Compilation Unit) */
1950         while (!lf.found && ret >= 0) {
1951                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1952                                  NULL, NULL, NULL) != 0)
1953                         break;
1954
1955                 /* Get the DIE(Debugging Information Entry) of this CU */
1956                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1957                 if (!diep) {
1958                         off = noff;
1959                         continue;
1960                 }
1961
1962                 /* Check if target file is included. */
1963                 if (lr->file)
1964                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1965                 else
1966                         lf.fname = 0;
1967
1968                 if (!lr->file || lf.fname) {
1969                         if (lr->function)
1970                                 ret = find_line_range_by_func(&lf);
1971                         else {
1972                                 lf.lno_s = lr->start;
1973                                 lf.lno_e = lr->end;
1974                                 ret = find_line_range_by_line(NULL, &lf);
1975                         }
1976                 }
1977                 off = noff;
1978         }
1979
1980 found:
1981         /* Store comp_dir */
1982         if (lf.found) {
1983                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1984                 if (comp_dir) {
1985                         lr->comp_dir = strdup(comp_dir);
1986                         if (!lr->comp_dir)
1987                                 ret = -ENOMEM;
1988                 }
1989         }
1990
1991         pr_debug("path: %s\n", lr->path);
1992         return (ret < 0) ? ret : lf.found;
1993 }
1994
1995 #ifdef HAVE_DEBUGINFOD_SUPPORT
1996 /* debuginfod doesn't require the comp_dir but buildid is required */
1997 static int get_source_from_debuginfod(const char *raw_path,
1998                                 const char *sbuild_id, char **new_path)
1999 {
2000         debuginfod_client *c = debuginfod_begin();
2001         const char *p = raw_path;
2002         int fd;
2003
2004         if (!c)
2005                 return -ENOMEM;
2006
2007         fd = debuginfod_find_source(c, (const unsigned char *)sbuild_id,
2008                                 0, p, new_path);
2009         pr_debug("Search %s from debuginfod -> %d\n", p, fd);
2010         if (fd >= 0)
2011                 close(fd);
2012         debuginfod_end(c);
2013         if (fd < 0) {
2014                 pr_debug("Failed to find %s in debuginfod (%s)\n",
2015                         raw_path, sbuild_id);
2016                 return -ENOENT;
2017         }
2018         pr_debug("Got a source %s\n", *new_path);
2019
2020         return 0;
2021 }
2022 #else
2023 static inline int get_source_from_debuginfod(const char *raw_path __maybe_unused,
2024                                 const char *sbuild_id __maybe_unused,
2025                                 char **new_path __maybe_unused)
2026 {
2027         return -ENOTSUP;
2028 }
2029 #endif
2030 /*
2031  * Find a src file from a DWARF tag path. Prepend optional source path prefix
2032  * and chop off leading directories that do not exist. Result is passed back as
2033  * a newly allocated path on success.
2034  * Return 0 if file was found and readable, -errno otherwise.
2035  */
2036 int find_source_path(const char *raw_path, const char *sbuild_id,
2037                 const char *comp_dir, char **new_path)
2038 {
2039         const char *prefix = symbol_conf.source_prefix;
2040
2041         if (sbuild_id && !prefix) {
2042                 if (!get_source_from_debuginfod(raw_path, sbuild_id, new_path))
2043                         return 0;
2044         }
2045
2046         if (!prefix) {
2047                 if (raw_path[0] != '/' && comp_dir)
2048                         /* If not an absolute path, try to use comp_dir */
2049                         prefix = comp_dir;
2050                 else {
2051                         if (access(raw_path, R_OK) == 0) {
2052                                 *new_path = strdup(raw_path);
2053                                 return *new_path ? 0 : -ENOMEM;
2054                         } else
2055                                 return -errno;
2056                 }
2057         }
2058
2059         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
2060         if (!*new_path)
2061                 return -ENOMEM;
2062
2063         for (;;) {
2064                 sprintf(*new_path, "%s/%s", prefix, raw_path);
2065
2066                 if (access(*new_path, R_OK) == 0)
2067                         return 0;
2068
2069                 if (!symbol_conf.source_prefix) {
2070                         /* In case of searching comp_dir, don't retry */
2071                         zfree(new_path);
2072                         return -errno;
2073                 }
2074
2075                 switch (errno) {
2076                 case ENAMETOOLONG:
2077                 case ENOENT:
2078                 case EROFS:
2079                 case EFAULT:
2080                         raw_path = strchr(++raw_path, '/');
2081                         if (!raw_path) {
2082                                 zfree(new_path);
2083                                 return -ENOENT;
2084                         }
2085                         continue;
2086
2087                 default:
2088                         zfree(new_path);
2089                         return -errno;
2090                 }
2091         }
2092 }